The in situ digestibility of dry matter (ISDDM) was assessed in three Holstein cows (560 ± 23 kg) with ruminal cannula. The proximal and Van Soest variables were analyzed with a complete randomized design, and for the variable ISDDM, a randomized block design was used. Significant differences for ISDDM (P≤0.05) between the Brachiaria varieties were found, with the highest percentages for the cv. B. decumbens Stapf and B. brizantha Marandú (63.9 and 63.2%, respectively). The diet with 10% C. cajan had average percentages of CP, NDF and ADF of 8.7, 70.7 and 47.6%, respectively, for all the Brachiaria varieties used in the study. It was found that diets with B. decumbens and B. Mulato II plus 10% of C. cajan were the best in terms of CP, NDF, ADF and ISDDM (9.3, 70.5, 46.4 and 64.1% and 8.6, 69.9, 50.3 and 63.5%, respectively). The results of this research showed that the value of CP meets the minimum requirements of nitrogen in the ration and that the ISDDM, DM, CF, NDF, ADF and ADL values are within the ranges reported for the genus Brachiaria.